1. New Cavity Classification:
A new classification of cavity based on the new concept has been proposed (Mount & Hume, 1997).
The proposed classification takes into account the fact that there are only three surfaces of the crown of a tooth that can be subjected to caries attacks.

2. These surfaces are:
Site 1: Pits and fissures on the occlusal surfaces of posterior teeth and other defects on otherwise smooth enamel surfaces.
Site 2: Contact areas between any pair of teeth, anteriors or posteriors.
Site 3: Cervical areas related to gingival tissues including exposed root surfaces.

3. A neglected lesion will continue to extend, so will the complexities of the restoration increase the sizes that can be readily identified include:
Size 0: Initial lesion at any site can be identified but not yet resulted in surface cavitation. It can possibly be healed.
Size 1: Smallest minimal lesion requiring operative intervention. The cavity is into dentin just beyond healing through remineralization.

4. Size 2: Moderate-size cavity
Size 2: Moderate-size cavity. There is still sufficient sound tooth structure to maintain the integrity of the remaining crown.
Size 3: There is already a split at the base of the cusp, or if not protected a split will likely develop.
Size 4: The cavity is extensive, following the loss of cusp from a posterior teeth or an incisal edge from an anterior.

5. Si / Sta concept
Lasfargues et al, 2000

6. Glass ionomer or resin sealant.?
Si / Sta 1.0:
Glass ionomer or resin sealant.?

7. Si / Sta 1.1

8. Prepared cavity
Restored teeth

9. Si / Sta 1.2

10. Si / Sta 1.3:

11. Si / Sta 1.4:

12. Si / Sta 2.1:
Proximal approach
Tunnel preparation
Slot preparation

13. Si / Sta 2.2:

14. Si / Sta 2.3:
Si / Sta 2.4:

15. Si / Sta 3.1:
Si / Sta 3.2:

16. Si / Sta 3.3:
Si / Sta 3.4:

17. Walls and Angles of Cavities
Black gave the following rules for naming the internal parts of cavities:

18. Rule I:
The surrounding walls of a prepared cavity take the names of those surface of the teeth adjoining the surface decayed, towards which they are placed. D F L

19. Rule II:
That wall of a prepared cavity which is to the occlusal of the pulp, and in a plane at right angle to the long axis of the tooth, is called the pulpal floor.
Pulpal floor
In case the pulp of the tooth is removed, and the cavity thus extended to include the pulp chamber; that wall is called the subpulpal wall.

20. Rule III:
That wall of a prepared cavity in an axial surface (parallel to the long axis of the tooth) and approximates the pulp, is called the axial wall.

21. Rule IV:
All line angles are formed by the junction of two walls along a line, and are named by combining the names of the walls joining to form the angle. B L D

22. Rule V:
All point angles are formed by the junction of three walls at a point, and are named by joining the names of the walls forming the angle. B D L

23. Lingual
Labial
Incisal

24. Lingual
Labial
Incisal

25. O D M

26. O D M

27. Cavo-Surface Angle
Dentino-Enamel Junction
Enamel Wall
Dentin Wall

28. THANK YOU